Bulked yarn



Sept. 23, 1969 B. DANIELS ET AL BULKED YARN Filed March 13, 196'? lATTORNEYS United States Patent O M U.S. Cl. 57-140 4 Claims ABSTRACT FTHE DISCLOSURE Bulked yarn comprises filaments which have a combinationof different sinusoidal crimp frequencies superimposed one on another asby means of a sequence of gearcrimping assemblies.

The invention concerns improvements in or relating to bulked yarn.

Bnlked yarn, in the context of this specification, means multifilamentyarn composed of continuous filaments of man-made material, as forinstance synthetic thermoplastic material, the filaments of which havebeen crimped, looped waved or otherwise distorted so as to impartincreased bulk to the yarn compared with its state before suchtreatment. It is usual to refer to the number of such crimps etc.,occurring in unit lengths as the Crimp frequency.

The bulked yarn of the invention which, in view of its versatility in anumber of ways and in a number of uses, is an advance over known bulkedyarns, comprises a multifilament yarn the filaments of which exhibitsinusoidal crimp of differing crimp frequencies.

By sinusoidal crimp we mean a crimp whose amplitude varies cyclically inboth positive and negative directions, bnt not necessarily with a puresine wave motion.

The relative proportions of the differing crimp frequencies may remainconstant along the length of the yarn or they may vary cyclically orintermittently, whether in random or in regular-fashion, along thelength. Furthermore the respective crimp frequencies may be constant orvarying in value, along the length of the yarn.

In a particular embodiment of the invention, the crimp is produced bycrimping between gear-wheels or other denticulated members. Using suchmeans, a yarn can be produced containing filaments each having acombination of the crimp frequencies, the one superimposed on the otheror others.

One convenient way of making the bulked yarn of the particularembodiment of the invention is by the process of crimping described inapplication, Ser. No. 622,640, filed Mar. 13, 1967, now abandoned, bywhich process heated multifilament yarn is drawn and crimped inapparatus including two assemblies of denticulated members and isoptionally cooled between said assemblies, and the construction andspeed of the members of one assembly differ, according to speciccombinations, from those of the other.

One typical bulked yarn according to the invention consists of a 400denier/50 filament yarn of polyhexamethylene adipamide, more than halfthe filaments of which are crimped with a combination sinusoidal crimpin which 38 crimps per inch are superimposed on 20 crimps per inch, andof the remaining filaments, some are crimped with a sinusoidal crimp of20 crimps per inch and the remainder with a sinusoidal crimp of 38crimps per inch. Skein length difference (L20-L5), is of the order of1.0-1.5.

3,468,l i8 Patented Sept. 23, 1969 ICC The reference to skein lengths Lin inches with numerals appended, are measures of the primary andsecondary crimp in the yarn determined by a test method in which acertain number of wraps for singles yarn, l5 to 3-fold heavy denieryarn) of yarn are taken around a l-metre reel, the skein so wound issuspended in hot water C.) and the length of the skein measured undertwo different loadings, the first being large enough to pull out thesecondary crimp (but allow the primary crimp to be manifested ordeveloped) and the second being insuicient to pull out the secondarycrimp (the actual loads depending on the size of the yarn in questionand being 20 and 5 grams respectively for the lower denier (400 denier)yarns, and 60 and 10 grams respectively for the higher denier (1040denier) yarns.

Such bulked yarn can be produced by a hot-gear-crimping process, asdescribed in said application, Ser. No. 622,640, in which two assembliesof gears are employed to act on the yarn between the snubbing-pin andthe draw roll of a drawing machine, the two assemblies differing fromone another, according to specific combinations, as to their speed andthe number of teeth per inch and degree of intermesh, and the yarnoptionally being cooled between said assemblies.

In one such process, the first gear-Wheel assembly had 38 teeth per inchand 0.021 inch intermesh, and the second assembly had 20 teeth per inchand an intermesh of 0.037 inch. The gear-wheels in both assemblies hadoutside diameters of 3.0445 inches. The gear-wheels of the firstassembly were run at 1400 r.p.m., and those in the second assembly at aspeed in the range 1600-1700 rpm., the feed roll speed being 512feet/minute and the draw roll speed being 2,000 feet/minute. The yarnwas heated by passage in 2 wraps around the snubbing-pin which wasinternally heated to 160 C. and between the two assemblies it was cooledby air from a nozzle emerging at a rate of 63 litres/minute.

In another such process, the first gear assembly had 20 teeth per inchand the second had 5 teeth per inch, the gears in both sets being of3.0445 inch outside diameter. The gears of each assembly were run at1100 r.p.m.; and the feed roll speed was 500 feet/minute, and draw rollspeed 1500 feet/minute. Under these conditions 3630 denier/68 filamentundrawn nylon 66 yarn was drawn and crimped such that the Skein lengthdifference (L60-L10) was 2.2 and the yarn was composed wholly offilaments in which the 20 crimps per inch frequency was superimposed onthe 5 crimps per inch frequency. The tension in the yarn between thegear assemblies was 395 grams; and between the second gear assembly andthe draw roll, 330 gra-ms.

In the above-described second process, if the draw roll was not used,the yarn with superimposed crimps was produced when the second gearassembly was run at 1350 r.p.m., and the first at 1300 r.p.m., the Skeinlength difference (L60-L10) being 1.7; and the tension between the gearassemblies being 540 grams, and balloon tension of the ring-spindlewind-up 70' grams.

The bulked yarn of the invention can consist of filaments the crimpfrequency of each of which differs intermittently, either in regular orrandom fashion, along their length. Such yarns can be produced by sovarying the conditions of crimping, e.g., by tandem gear-wheelassemblies, that first one crimp frequency predominates and thenanother. In the case of gear-wheels, the crimp frequency of the assemblyhaving the greater peripheral speed at any given time will tend topredominate; and variation of the relative speed setting will lead tovariation in the nature of the crimp in the yarn, from a state where onecrimp frequency wholly predominates through a state where that crimpfrequency predominates but the other frequency is also present to aminor degree, though the true superimposition state, thence to the stateWhere the other crimp frequency predominates but the rst one is alsopresent to a minor degree, finally to the state Where the second crimpfrequency Wholly predominates.

The bulked yarn of the invention is advantageous in that the crimps inthe filaments are not in register for any substantial length of yarn, asmay be the case for instance with conventionally gear-crimped bulkedyarns; and in that the yarn is more versatile than ordinary bulkedyarns, being useful across a Wider spectrum of fabrics.

The bulked yarn of the invention is illustrated by the attachedphotograph of a single iilament showing a combination of low and highcrimp frequencies along its length.

The latter advantage results from the fact that the optimum crimpfrequency for, say, good stitch clarity n a knitted fabric is contraryto the requirement for good fabric bulk, and vice versa. The bulked yarnof the invention, especially when it contains iilaments having one crimpsuperimposed on another, effectively meets both requirements by virtueof the presence of both crimps.

The bulked yarn of the invention is preferably cornposed of filaments ofsynthetic thermoplastic material, as for instance nylon, Terylenepolyester libre, and polyproylene; but equally it can be composed ofother manmade filament materials, like cellulose acetate.

We claim:

1. A bulked multilament yarn containing laments which exhibit sinusoidalcrimp of differing crimp frequencies, characterised in that certain atleast of the filaments have a combination of different sinusoidal crimpfrequencies, the one superimposed on the other or others.

2. A bulked multilament yarn according to claim 1 in which, of theremainder of filaments in the yarn, each has one or the other of saidcrimp frequencies singly.

3. A bulked multiiilament yarn according to claim 2 having two saidcrimp frequencies, one of high crimps per inch and the other of 10Wcrimps per inch, and in which in the remainderV there are laments withall low crimp frequency and iilaments With all high crimp frequency. Y l

4. A bulked multitilament yarn according to claim 2 in which thepredominance of the respective crimp frequencies varies along the lengthof the yarn.

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2,997,838 8/1961 Sinski 57-140 XR 3,013,379 12/ 1961 Breen 57-140 XR3,175,348 3/1965 Bloch.

3,188,790 6/1965 Hebeler 57-140 3,208,125 9/1965 Hall et al. 57-140 XR3,255,580 6/1966 Garner 57-140 3,259,953 7/ 1966 Baer.

3,262,257 7/1966 Martin 57-157 XR 3,263,298 8/1966 Holton 57-157 XR3,309,855 3/1967 Stoll et al. 57-157 XR DONALD E. WATKINS, PrimaryExaminer U.S. Cl. X.R.

